As new vaccines become available, the need for vaccine economics research will increase due to budget constraints for vaccination programs. The objective of this research study is to inform vaccine policy recommendations under consideration by the Advisory Committee for Immunization Practices (ACIP), CDC, and other state and local decision makers. Specific Aims: The proposed research studies addresses key issues in vaccine policy: (1) potential health and economic benefits of improved vaccination coverage;(2) societal values for vaccine risk-benefit tradeoffs;and (3) public preferences for adolescent and adult vaccination settings. Investigators and Environment: This application requests continued support for a highly successful collaboration, the Joint Initiative in Vaccine Economics (JIVE), which is now in its tenth year. The JIVE project includes investigators with broad experience in a wide range of economic evaluation and decision science methods including cost-effectiveness analysis, benefit-cost analysis, contingent valuation, and conjoint analysis, as well as related expertise in modeling methods. The Joint Initiative in Vaccine Economics has a long history of supporting collaborative research among co-investigators at Harvard University, the University of Michigan, and the Centers for Disease Control and Prevention (CDC). Innovation and Research Strategy: The overall approach is to use economic and decision analysis methods to provide evidence to inform vaccine policy decisions. The initial study will measure the economic value of changes in vaccination coverage on health outcomes, costs, and cost-effectiveness, by developing a theoretical model of the economic value of vaccination for the US and an empirical model using dynamic simulation modeling. We propose two additional studies on topics anticipated to have high policy impact: risk- benefit tradeoffs for vaccination-related adverse events;barriers and facilitators to adult vaccination. The proposed methods draw on economic and modeling approaches, including dynamic simulation models, multiple-criteria decision analysis, and conjoint analysis, that have not been widely applied to vaccine policy questions. Jointly with investigators from CDC, the research team will identify topics of policy relevance and develop the appropriate research plan.